The present invention relates to a handle for a medical instrument which has two jaw parts movable independently of one another.
A handle of this kind is known from DE 694 3 583 T2, corresponding to EP 0 640 319 B1.
A handle as cited initially is provided for a medical instrument that has two jaw parts movable independently of one another. Forceps of this kind are used in endoscopic surgery, usually as multifunctional instruments, for example in order to cut tissue with the one jaw part and to grasp it with the other jaw part for removal of the tissue from the body. Accordingly, the one jaw part is configured as a cutting tool, whereas the other jaw part is shaped as a grasping tool. The two jaw parts are movable independently of one another, i.e. they can be closed and opened independently of one another. Both jaw parts can also possess a cutting function or a grasping function.
A handle of this kind for a medical instrument having two jaw parts movable independently of one another, and correspondingly two handle elements movable independently of one another, should be configured so that the physician can easily operate the handle without relearning the manner of operation of such an instrument, or needing to become accustomed to a new manner of operation.
With a predominant number of medical instruments, physicians are accustomed to a handle that is operable in scissor fashion, such as is known, for example, from DE-A-44 44 025 and sold by the company Karl Storz GmbH & Co., Tuttlingen, Germany, under the trademark "Takeapart." The advantage of these handles is that they can be held and operated with the thumb and the index and/or middle finger in the manner of a scissors. The two handle elements are configured such that they can be held with a hand position in which the back of the hand extends substantially vertically, which has the advantage that the wrist is then straight. Handles of this kind that are to be operated in scissor fashion have proven to be particularly ergonomic in the context of medical instruments, since it is possible to work in fatigue-free fashion with instruments having handles that are operated in scissor fashion.
The handles of scissor-like configuration described above have, however, hitherto been provided only for those medical instruments that have either only one movable jaw part or two jaw parts movable together. These known handles accordingly have only one movable handle element and one immovable handle element.
The aforementioned DE 694 03 533 T2 discloses a handle which that document refers to as a "manipulable surgical hand," which has three movable handle elements in order to allow tools at the distal end of a shaft to be actuated independently of one another. Of the three movable handle elements, one forms the thumb handle element and the other two form handle elements that are operable with the index and middle fingers. The handle elements actuable with the fingers are arranged distally from the thumb handle element, and laterally on the handle body. With this handle element arrangement, it is said that the natural movement capabilities of the human hand can be transferred in lifelike fashion to the tools at the distal end. This handle has at its proximal end a bracing plate against which the hand surface of the hand holding the handle rests; the handle is intended to constitute a "mechanical glove" into which the thumb and two fingers of the human operator can be inserted. This handle is accordingly always operated simultaneously with the thumb, index finger, and middle finger, one handle element on the handle body being allocated to each of these fingers. The handle elements are arranged, in this context, in the shape of a triangle. Leaving aside the fact that this handle is of very complex design because of its additionally provided functions, the configuration of this handle does not correspond to that of a scissor-handle arrangement. Instead, the thumb, index finger, and middle finger are spread apart in front of the hand when they engage into the respectively provided finger rings. Working with this handle requires long practice and particular dexterity.
In medical instruments having two jaw parts movable independently of one another, it is occasionally necessary to rotate the instrument as a whole about the instrument axis in order, for example after tissue has been detached with the one jaw part, to bring the other jaw part to the detached tissue in order then to grasp it with that jaw part. In this context, the entire instrument (including the handle) must be rotated as much as 180.degree., depending on the position of the jaw parts.
This is possible only with difficulty with the known handle cited above, since the thumb handle element does not permit rotation about the longitudinal axis of the handle.
A handle for a medical instrument having two jaw parts movable independently of one another and, correspondingly, two handle elements movable independently of one another is furthermore disclosed by U.S. Pat. No. 5,403,332. This handle is arranged in the shape of a T at the proximal end of the instrument shaft. The two movable handle elements protrude laterally from the instrument shaft, and are located distally in front of the proximal stationary handle. This handle is held in such a way that the rear transverse grip lies in the inner surface of the hand like a bar, so that the index and middle fingers and ring finger can fit around the movable handle elements configured as buttons, and can pull them proximally toward the transverse grip in order to actuate the jaw parts. This embodiment of a handle also does not correspond to that of a scissor-like handle arrangement.
A medical forceps having two jaw parts movable independently of one another and two handle elements movable independently of one another is also known from U.S. Pat. No. 2,214,985. A third handle element is arranged distally in front of and centeredly between the movable handle elements. The two movable handle elements and the immovable handle element each have a finger ring through which a finger or thumb can be inserted. The third, immovable handle element has a finger ring that is arranged in a plane perpendicular to the longitudinal axis of the forceps, this plane moreover running obliquely with respect to the planes of the two finger rings of the movable handle elements. This handle is held in such a way that the index finger is inserted through the distal immovable handle element, while the thumb and middle finger are inserted through two proximal laterally arranged finger rings. The result is that handle arrangement does not represent a handle arrangement that is operable in scissor fashion, as is known in medical instruments having only one movable jaw part or two jaw parts movable together, to which surgeons are accustomed.
It is therefore the object of the invention to develop a handle of the kind cited initially, for a medical instrument that has two jaw parts movable independently of one another, in such a way that the handle is ergonomic, that it becomes possible to work in fatigue-free fashion with the instrument, and that handling of the handle in order to actuate the two jaw parts is simplified.